Stuck on a practice problem and the explanation in your notes will not click? Lensia is a Chrome extension that works like an AI homework scanner built into your browser, but it does not stop at a single scan. You press Ctrl+Shift+X, drag a box around a problem, and a worked explanation floats up on the page in seconds. Then, when one answer is not enough and you want to actually understand the method, you carry it into the sidebar chat and keep asking until it makes sense. The scan pulls the question in; the sidebar is where you learn it. Install Lensia free and have your first explanation on screen in under a minute.
Lensia is a study aid. Use it to understand concepts, make your own practice, and check your work after you have attempted it. Using it during a graded assessment where AI is restricted is academic dishonesty. Read your school's academic-integrity policy before you decide where any AI tool belongs.
What an AI homework scanner actually does
Most tools called "homework scanners" want you to snap a photo of a textbook with your phone, then squint at one answer. Lensia works right on your computer and reads any problem already open in your browser, inside the study material you are using. Press Ctrl+Shift+X, drag a box, and the text inside it is read on your own machine first, so the screenshot stays on your device when the text comes through clearly. You are not uploading your coursework to some outside server.
It reads the question the same way whether it is on Canvas, Moodle, Blackboard, WileyPLUS, Pearson MyLab, McGraw-Hill Connect, Schoology, or a PDF in a tab. For the full walkthrough of both surfaces, read how Lensia works.
The scan is fast; the sidebar is where you learn
A scan gives you one explanation. Understanding usually takes a few more questions, and that is the whole reason the sidebar chat is the main way to use Lensia. Open it from the Lensia icon in your Chrome toolbar, and a chat docks in Chrome's side panel next to your work. It is on every plan.
What makes it the real workspace is that it holds a conversation instead of a single answer:
- Conversation history stays between sessions, so last week's scanned problem is still there when the exam comes around.
- Bookmarks save the explanations you know you will reread.
- A model picker lets you start on a fast model and switch to a stronger one mid-thread when a problem needs more careful reasoning.
Here is the loop that works: scan a problem with Ctrl+Shift+X, read the floating answer, then open the sidebar and type "why does step two work?" or "give me two more like this." Attempt those yourself, paste your work back, and ask where you went wrong. That back-and-forth is what moves a problem from "I saw the answer" to "I can do it." For the study habits that make this pay off, read the study smarter guide.
Scanning options on the floating panel
The scan itself has more to it than one keypress:
- Capture Mode is the default:
Ctrl+Shift+X, drag, read. Best when the question is already on your screen. - Ask Mode is a switch on the same panel that turns it into a typing box. Write your own question and attach up to three images from your screen or device, which is handy when one screenshot cannot hold the whole problem or you want to compare two figures.
- Quick Capture (
Ctrl+Shift+F) repeats your last scan area without redrawing the box, so a page of similar practice items becomes one keypress each. - Stealth toggle (
Ctrl+Shift+E) hides the panel completely and brings it back with the same keys.
If the text in your scan is hard to read (handwriting, a low-resolution PDF, an equation saved as a picture), Lensia sends the image itself to a vision-capable model that reads it by looking. You do not switch anything; the fallback runs on its own.
Scanning different kinds of problems
- Math and science: include the full problem, the numbers, and the units in your scan. Turn on reasoning mode for multi-step work, then compare the steps against yours. More in AI for math homework.
- Multiple choice: scan the question with every answer choice so the AI can explain why one holds up and the others fall apart. See AI for multiple-choice practice.
- Short answer and definitions: scan the prompt, read what a strong answer covers, then write your own version to lock it in.
- Diagrams and charts: the panel switches to image mode on its own and reads the picture directly.
What each plan unlocks
Every tier signs in with Google. Sign in once to activate and start scanning.
Free covers the starter usage allowance, the sidebar chat, the scanner panel with Ask Mode, Quick and Standard models, and the Lensia Max router, which picks a fitting model per question and takes 15 percent off the cost.
Basic adds about ten times the usage, the reasoning toggle, custom instructions, web search and fetch URL in the sidebar, and the Advanced models like Claude Sonnet 5 and GPT-5.5 for the hardest problems.
Pro has the highest allowance and adds agent mode in the sidebar (it can read your open tabs, take a fresh screenshot, and chain steps) plus Auto-Solve Mode, which currently works on Vocabulary.com only. Every other platform uses the manual scan flow. For a plan-by-plan comparison, read the best AI tool for college students guide.
Start scanning your homework
Setup takes under two minutes. Install Lensia from the Chrome Web Store, sign in with Google, and scan the first problem that has you stuck. Read the floating answer, then move to the sidebar and keep asking until the method is yours. That is the difference between copying an answer and actually learning it.
Install Lensia today and turn any on-screen problem into an explanation you understand.